Spark plug



Se t 16, 1924;

' H. MANSFIELD SPARK PLUG Filed April 5, 1924 INVENTOR v JYOra ce Mansfield,

. BY g A'ITORNEY Patent Set. 16, 1924.

NEW YORK, ASSIGNOR F ONE-r. a: 1: Ire-Ii OE BROOKLYN, YO a;

Application filed April 3,

To all whom e't may concern:

Be it known that 1, Homes Mansrrnnn, a citizen of the United States, and resident of Yonkers, in the county of Westchester 5 and State of New York, have invented certain new and useful Improvements in S ark Plugs, of which the following is a specification. I My present invention relates to an improvement in high tension spark plugs for lgnitin' the fuelcharge in caloric engines, and it as for its principal object a structural arrangement of the terminal portions 4 of the said plug whereby to increase the firing power thereof through the increase in the number of sparks'developed by the peculiar surfaces of the coacting terminals. My invention also has for its object that improvement in the associated terminal 29 structures whereby to automatically prevent short circuitin of the terminals and to afiord means w ereby any bridge of carbon or oil at the terminal broken down and destroyed, thereby leaving the plug entirely free of any deleterious matter that might form thereon and thereby prevent the operation of the lug.

M invention also contemp ates the structura arrangement of the coacting electrode 30 parts whereby the same may be readily manufactured in an economical and practical'manner.

l-In the drawing herewith, Fig. 1 is a sectional view of my device, taken on the line 1-1 of Fig. 2;

Fig. 2 is a bottom view of my device;

Fig. 3 is a fragmentary view of the bot-' tom portion of my construction showing the action of the coacting terminals. 7 in the construction my plug is substantially made according to present standard practice to "the entent that it comprises a base shell I, having mounted therein an insulating core 2', which may be madeof 4:5 porcelain 'orother suitable Vitreous material, and in the center of which is located a central stem electrode 3 which is held mounted in operation relation in said core by means of a threaded lock nut 4' and for the purpose of permitting the afixed gap is immediately 1924. Serial K0. 7Q3,942.

proof compression gasket 9 is also utilized at the bottom of the shoulder 6 between said shoulder and the seat 7 in the usual manner.

I will now describe the novel portion of my plug which consists in the constructional details such as is outlined in Fi 1 at the terminal or electrode end, of sai plug which is threaded in the'usual manner as at 10 to be mounted in an engine cylinder.

My novel construction consists in cupping the lower end of the electrode 3 as at 12, Q

and the'lower electrode end of the spark plug 11 so that between these .two members, which are normally spaced apart, there is located a loose, cooperating floating ball electrode 13, said cupping acting as a socket for the floating electrode ball 13, which the Fig. 1 is shown as resting in the cupping electrode 11 of the base 1.

These. cupped members form a substan tially spherical contour which is of such a diameter and; of such spaced relation that they loosely maintain within their zone the metallic-ball '13, preferably made of steel, and in such a manner that the ball is at all times loosel held for permitting rapid vibration and rotation during the operative use of the plug. p, y

It will be ascertained by examining Fig.

2, which is a bottom view of the plug showing the lower plug terminal 11, that is substantially in the form of a bridge across. the 'bottom'of the plug, leaving two openings A and B between the side walls of the plug, thereby leaving an open space for the passage of gas into and out of the lower chamber 15 of-the plug. The lowerelectrode or brid e 11 is also provided with an openingl l t erein which is of sufiioiently large diameter to expose, as indicated in Fil a part substantial of'surface of the ba to the action of the gases wit the cylinder and yet support the ball properly in inoperative position. it will also be noted that the bridge piece. 11 is contoured in such a manner as 0 to form a swell G on both sides so as to .of the cup? which it is separate allow the formation, midway of said bridge, which is more fully shown in section in igs. 1 and 3. t

I have discovered in actual practice that, with a floating terminal construction of the type herein disclosed, during the firing action, the lower edges of the cupped terminal 12 discharge a rim of sparks to the ball which may beresting upon the bridge ll, but should the ball be midway between the two terminals 11 and 12, then there is a double rim or sparks formed between the ball and the two opposing terminals from I have also ascertained in action that the ball vibrates very rapidly as well as retates, due to the explosive action of the gases within the cylinder and the vibration of themotor and that as a result the-ball duringaction is never at rest, but is moving about and is rotating at a very high rate of speed, but always within arcin distance of either or both terminals, and th s action is ent1rely due to the rapid vibration of the engine during its operation. llhis rapid vibratoryaction keeps the terminal cup edges and the ball clean and this is evidenced by the fact that while the remainder of the plug, as usual, becomes carbonized, the ball and cup edges always retain a bright,'clean condition and break down, or throw ofi' all short circuiting conditions and insure a clean, open path for the igniting current to pass therebetwen.

I have used this plug in old engines which were so badly worn that lubricating oil, havand usefully operative.

in reached the combustion space of the cyl- 1n er, would short circuit an ordinary plu and yet this plug continued to. fire an eventually dry out the cylinder, through the formation of carbon, by the burning of such 011 and eventually cause the cylinder to become normally dry, fairly compression tight It is further obvious that there is also conslderable novelty'in the manner of the construction ofboth the stem electrode 3, due tots cup-shaped electrode end 12, as an article of manufacture, and this also applies to the spherically seated electrode bridge 11, in the shell or base 1. i

It is obvious that modificationsmay be made in the details of my device, by one skilled in the art, without avoiding the scope of the invention.

Having thus described my inventiomwhat I claim is: I I i 1. A spark plug comprising a pair of opposed cup-sha ed electrodes each provided with an annu ar contact edge; and a conshaped electrodes close sides of the/bridge; the m incense ductive ball loosely retained between and by of the cups to prevent extended contact with the cups except at said edges, whereby packing of carbon in the cups is avoided.

2. A. spark plug for internal combustion engines, comprising a pair of opposed cupagainst communication with the exterior of the cylinder each provided with an annular contact edge; and a conductive ball loosely retained between and by said edges free durin explosion for intermittent contact with sai edges.

3. A spark plug for internal combustion engines, comprising a pair of electrodes forming opposed cup-shaped electrodes closed against communication with the exterior at- -mosphere and each provided with a sharp annular contact edge; and a conductive ball loosel retained between and by said edges free uring explosion for intermittent contact therewith and having a diameter slightly greater than the inner diameter of said annular ed es and difi'erent from the diameter'of the laces of the cups to prevent extended contact with the cups except at said edges. Y

d. A'spark plug for internal combustion engines, comprising a pair of electrodes closed against communication with the exterior of the cylinder providing opposed spaced annular coaxial contact faces; and a conductive ball loosely retained between said faces intermittently contact'able therewith llii) and free to spin on said faces during exploing through said core and provided with a cupped lower end forming'an annular sparln ing edge; a thin sheet metal lower electrode member secured to the lower edge of said shell and forming a bridge across the lower part of the shel leaving ogenings at the part or said bridge being formedwith a central opening forming an annular sparking edge; and a conductive ball loosely retained between and by said edges and contactable therewith.

7. A spark plug comprising a base shell; an insulating core therein; an electrode passing through said core and provided with a cupped lower end forming an annular sparkllO moeee v ing ed e; 'e lewer electrode member secured a conductive hell loosely disposed between to the ower edge of said shell and forming e said edges and contacteble therewith. bridge across the lower part of the shell leavmg large openings 7 at the sides of the New York and State of New York, the 2d 5 bridge; the midi pert of said bridge being day of April, A. D. 1924.

' cup-shaped end formed with e eentrel open 7' ing forming an. 111msperking edge; and EEORACE NSFIE.

Signed at New York; in the county of 10 i 

